Blow torch



NOV- 6, 1956 F. L. scHwE'n-zER 2,769,487

BLOW TORCH 2 Sheets-Sheet 1 Original Filed Feb. 8, 195C IN VEN TOR w'z 'c//WE/ r2.5@

mw, c; @www Arme/ve ys NOV- 6, 1956 F. L. scHwElTzx-:R 2,769,487

BLOW TORCH original Filed Feb. 8,'1950 2 Sheets-Sheet 2 MM v6@ mw M my L mw E@ W Y Y; W@ XK, QA. m \h.h mwa. ww We* v1 W// L. J.

United States Patent BLGW TORCH Fritz L. Schweitzer, Aurora, Uhio Continuation of appiication Serial No. 143,956, February 8, 1950. This application January 5, 1953, Serial N 329,490

' Claims. (Cl. 158-33) The present invention relates to blow torches and other self-contained apparatus for producing a concentrated high temperature flame, and more particularly to certain, improvements over known apparatus of this type. whereby the same may have substantially improved operation with regard to heat output and to facility in handling and operating.

This application is a continuation of my co-pending application Serial No.V 143,066, tiled February 8, i950, nowabandoned, and concerns certain improvements over apparatus disclosed and claimed in my prior U. S. Patent No. 2,539,595 entitled Blov/torch.

In my above mentioned U. S. patent I have disclosed an improved blow torch comprising a tank or body member for the reception of fuel, a burner nozzle secured inheat conducting relation to the tank, and a vaporizing chamber positioned in intimate heat conducting relation to the nozzle; the arrangement being such that heat generated at the nozzle of the torch is, in part, conducted into the fuel reservoir to vaporize the fuel therein and to generate. pressure for operating the torch, the fuel passing from the reservoir to the nozzle by way of the vapon'zing chamber wherein the fuel is highly superheated and conditioned for immediate and rapid combustion at the nozzle.

My prior invention is advantageous in many respects, and particularly in that no pumping or other artificial creation of operating pressure is required. However, this same apparatus has been found not to be entirely satisfactory in certain other repects such as, for example, predictibility of performance in cold or otherwise excessively unfavorable weather conditions and operation ininverted and vertical positions. Accordingly, it is the ultimate object of this invention to provide a blow torch embodying certain of the advantageous features of my prior invention while combining therewith certain additional advantageous and novel features thoughtl to materially improve the overall operation Vof my prior apparatus.

More specilcally, the invention seeks to provide a blow torch of the type having a heat conductive body and a burner nozzle mounted directly thereon which is characterized by improved means for vaporizing-4 and superheating, fuel passing from the body to the nozzle whereby operation of the torch may be rendered uniformly predictible under substantially all conditions of operation and substantially without regard to the orientation of the burner nozzle during use of the torch.

Another and particularly important object of the invention is the provision in a blow torch of the type herein contemplated of an improved arrangementfor Vaporizing and superheating fuel prior to the combustion thereof wherebyv heat supplied from the burner nozzle for the purpose ofrsuperheating the fuel may be properly correlated with the rate at which the same is consumed at the nozzle of the torch under substantially all conditions of operation.

Another object of the invention resides in the pro- Patented Nov. 6, 1956 ice vision in a blow torch of the type having a heat conducting body and a burner nozzle mounted directly on a wall of such body of improvements relating to the construction of the body member whereby the nozzle may be more readily mounted thereon and whereby more elhcient transfer of heat between the nozzle andthe interior of the body may be realized. And it is further within the scope of the above object to provide a.V blow torch as above characterized wherein the flow or transfer of heat from the burner nozzle tothe interiorl of the tank or body member is substantially uniform'regardless of ambient conditions, such as wind velocity a'nd air temperature for example, so that the torch may beY as elfectually utilized out-of-doors as within a protected enclosure.

Yet another object of the invention resides in the provision of a blow torch of the general type described wherein the tank or body member of the torch is provided with a heat conductive wall of relatively heavy proportions and having an appropriately contoured eX- ternal surface whereby the burner nozzle of the torch may be mounted directly on and in intimate heatexchange relation to the wall and whereby a superheating chamber for fuel may be housed wholly within such heat conductive wall. The above arrangement further contemplates mounting the nozzle in heat exchange relation with the heat conductive wall along a substantial portion of the longitudinal extent of the nozzle and aligning the superheatingchamber adjacent such portion whereby heat from the nozzle will be transferred to the superheating chamber and to the interior of the tank in predetermined relative proportions properly correlated to insure operation of the torch in the manner desired.

Another object of the invention is the provision of; a blow torch having the above described advantages and characteristics which is of novel and highly improved construction whereby .the torch may be readily vand inexpensively manufactured andassembled andwherebythe assembled torch is substantially more ruggedl and compactV than prior apparatus ofthe same generaltype.

Another and .more specific objectV of the invention resides in the `provision of aV blowy torchY embodying the above novel features, including an Velongated restricted chamber or passage forsuperheating uelxprior. tothe combustion thereon, whereinV suchL chamber or passage may be easily Vconstructed and assembled into-thetorch and is providedrwith means whereby accessv may beeasily had to the chamber for the purpose of cleaning .the same, for example, if and when necessary.

The above and other objects. and advantagesof the invention willy become apparent upon full consideration, of the following detailed specification and accompanying, drawing` wherein is disclosed a certain preferred embodiment of the invention.

In the drawing:

Figure l is a longitudinal section View` of a blowv torch constructed in accordance with, theteachings of .my invention; p

Figure 2 is a top plan` view of Vthe apparatus `.of Figa ure l;

Figure 3 is an. enlargedv fragmentary section View `of the apparatus of Figure l illustrating CertainV features. of the construction thereof; and

Figure 4 is a 'fragmentary section View taken generally along line lV-IV of Figure 3.

Referring now to the drawing, the numeral 1t) desig-` nates generally a or body. member of my improyed torch which, in accordance .with the teachings of theVA invention, is provided with an integral top wall l1 of relatively heavy proportions. Formed integrally ywiththe top wall 11 is an upwardly extending valve block il and a tubular nozzle holder 13 having a horizontal bore thereto the side walls of the tank orsecured by anyother suitable means. ln the preferredrembodimentofthe in- .vention the bottom wall 61 is provided centrally with a threaded filler 4opening 62 which is engaged andV closed by a similarly threaded flanged closu'rep'lug 63. As Will be observed, the arrangement of the bottom inember 61 and opening 62 is such that when the Ytank 1t? is held in vinverted position the bottom 61 forms, in effect, a funnel which facilitates pouringfuel into the tank through the opening 62. i

In accordance with the teachings of the invention the tankis constructed of a highlyheat conductive material, and preferably of aluminumwhich, in addition to beingwsighly heat conductive, is relatively light weight and therefore easily carried about. Furthermore, the use of aluminum material for the tank 16 peirnits the valve block 12, nozzle holder 13 and side walls to be formed integrally from a single body of metal, as by an impact extrusion processV for'example. This isV desirable not only from the standpoint of ease and economy of manufacture but additionally because of the uniformity of heat transfer properties inherent in tank so constructed.

Received in the nozzle holder 13 and extending outwardly thereof is a cylindrical burner nozzle 15 which may be formed of brass and which frictionally engages the interior side walls of the holder 13 by means of spaced raised annular lands 16 so that the nozzle 15 is firmly held in its assembled relation with the holder 13 as illustrated in Figure l. In actual practice theV lands 16 are raised but al slight amount, the drawings being exaggerated to more clearly depict the arrangement. 1n accordance with conventional practice the nozzle 15 is provided with a restriction 18 and a plurality of radial openings 19 to YimproveV combustion of fuel within the nozzle.

Mounted fon the valve block 12, in Va horizontal threaded bore 29 provided therein, is a ietV nozzle 2t) havmg a fuel passage therethrough and a restricted 'oritice 40 as shown in Figure 3. The jet nozzle 20 is in communication with the interior of the tank 10 by means of a valve assembly 21 and superheating chamber to be hereafter described whereby fuel may be discharged into the burner nozzle 15 to sustain combustion therein. The valve assembly 21 comprises a tubular valve seat member the lower end of which is maintained in seal. ing engagement with a shoulder 23 of a threaded bore 22 provided in the Valve block 12. A passage 24 leads into the lower end of the bore 22 and communicates through the tubular member 25 and a bore 28 provided in the side thereof with the iet nozzle 20. The tubular member 25 is provided at 4its upper end with threads for engaging a valve stem which is adapted to engage a valve seat 27 and thereby close o communication between the passage 24 and jet nozzle 20. An enlarged knob 36 is secured at the upper end of the valve stem 30 whereby the same may be grasped and rotated by an operator to move the stern into and out of sealing engagement with'the valve seat 27.

To prevent leakage of fuel about the valve assembly I provide a sleeve 32 which surrounds the tubular member V25 and a portion of the stern 30 and threadedly engages Ythe bore 22 in valve'block 12. The upper end of the sleeve 32 is recessed internally for the reception of packingV material 33 and a packing washer 34, and threaded externally foi the reception of'a packing nut 35, all in accordance with conventional valve construction.

In the illustrated embodiment of the invention I conveniently utilize the upwardly extending sleeve 32 to 'cured to the sleeve 32 by means of a nut 39 as shown in Figurerl. Y

As shown in Figure 3, the top wall 11 of tank -10 is provided with a thickened portionV which. is disposed longitudinally of the wall 11-and directly below the burner nozzle 15. Located Within the above mentioned thickened portion, immediately below the burner nozzle,'and

Vextending substantially throughout the length of the top Y wall 11 is a bore 44 which is threaded at its open end and provided with a shoulder 52 intermediate its ends.

Tightiy received within the bore 44 is a tubular mein Y ber 4S which is provided near its outer endrwith a shoulder complementary to and abutting shoulder'52,`andV which is provided inwardly of the shoulder with continuous threads 59 of Vrelatively tine proportions. The

threads 513 are adapted in cooperation with the sidewallsV of the bore 44 to form an elongated and relatively restricted passageway 51 communicating at its router end with passage 24, leading to valve21, and at its inner end with the innermost end of the bore 44, the tubular member'48 being shorter than the bore 44 Vas shown in.

Figure 3, whereby to provide a clearance space between the extreme inner ends of the bore 44 and tubular member 48.

Tightly received within the tubular member 48 is a rod 49 having continuous threads 54 engaging the interior side walls of the member L38 and defining 'in cooperation therewithV a second elongated and relatively restricted passageway 55 which communicates at its inner end with the above mentioned clearance space, and hence also with passage 51, and at itsk outer end with the outer portion of the bore 44. Also communicating with the outer portion of the bore 44 is a'fuel passage 46 leading to the interior of the tank itl. jThe extreme outer end of the bore 44 is closed oby means Vof a closureplug 45',V so

that there is formedY by the above described assemblya Y continuous fuel passage Vleading from the tank 10,'throughk passage 46, passage 5v5 between rod 49'and'tubular member.48, and passage 51 between tubular' member 48 and the walls of bore 44, these passages leading ultimately toy the jet nozzleV 29 through passage 24 and Valve assembly 21." The arrangement is such that fuel passing from,v the tank '10 to the jet nozzle 20 must rst pass*V through a highly elongated tortuous andl relatively restricted'pasf sage, all of which passage is confined within` the heat i conductive` top wall 11 of the tank,rimmediately ad` jacent the burner nozzle 15.

To avoid clogging of the relatively restricted passages 55 andl 51 with foreign particles and other fuel Vimpurities I provide a filter screen 56 at the outer end of the tubular member 48 which strains all fuel passing from passage 46 into the first restricted passage 55. The screen 56 is preferably retained in position by means of a disc 57 having a plurality of openings 59 therein, which disc ,is f

in turn retained in position by means of a spring 53 carried by the closure plug 45. Removal of filtered foreign matter may thus be accomplished by merely re- Y moving the closure plug, disc, and screenV as will be readily apparent. V p f In the operation of v`my improved torch, the tank 10 is rst filled with a suitable volatile inilammable liquid fuel, such as gasoline for example.v The tank 10 is then heated artificially to vaporize the fuel within the tank, creating a pressure therein'and causing thevaporized fuel to pass to and out of the jet nozzle'20. Combustion of the fuel then takes place in the burner nozzle 15 causing the latter to become highly heated.YV

In the illustrated embodiment ofA the invention/artificial heating of the tank and surrounding parts is facilitated by providing wells 14 in the top wall 11ofV the tank, which wells may be tilled with torchrfuel, Yfor example, and ignited. It is contemplated that the wells 174 will hold a quantity of fuel which is surcient to assure` proper starting of the torch as soon las all orV substantially all of the fuel in the vwells has been consumed. e Y

Heat from' the nozzle 15 is in part ydissipated into-the surrounding air andin part 'transferredrby conduction to the aluminum nozzle holder forming an integral part of the top' Wall 11 and tank 10. These lastmentioned members are accordingly heated by conduction from'the nozzle holder 13, and the fuel Within the tank lil'is therebyvaporized, Vand operating pressureV thereby generated, in a regenerative process by heat derived from combustion of' the .fuel at the nozzle' 15. Artiiicial'heat may therefore be discontinued as soon as heat is being transferred from the nozzle i at a rate sufficient to sustain operating pressurein the tank, which, in actual practice isalmost immediately after combustion is initiated at the nozzle'15.

The-elongated and relatively restricted passages 55 and 51; being housed Wholly WithinA the top WallV 11 of the tank 10, are yin intimate heat exchange relation with the nozzle 15 and nozzle holder i3. Therefore a substantial portion of the heat conductedaway from the nozzle 15 is transferred to the vaporized fuel flowing through these passages to the jet nozzle 2Q. The fuel isfthus brought to a highly superheated condition immediately prior to its discharge from the jet nozzle 20 whereby combustion at the burner nozzle 15 is immediate andthorough.

And it is to be particularly noted that the heat which is transferred to the passages 55 -and.51, forming in'eifect a fuel superheating chamber, is at all times indirectV proportion to the rateat which heat. is transferred to the main body of the tank 10, which ultimately determines the rate at which fuel is consumed at the nozzle of the torch. Thus, the greater the rate of fuel consumption, the greater transfer of heatV to the superheating chamber. The result being a substntially uniform preconditioning of the. fuelvbefore combustion thereof regardless of the rate Vof consumption.v

Et'WlLfUrther-beobSerVed that While the superheating chamber for thefuel comprises a highly elongated passage, all of which is housed within the top wall 11 and therefore in .intimate Yheatvexchange relation to the burner nozzle. i5, the total volumevof the passage is quite small. This arrangement limits the quantity of fuel which may at any'timefbe contained within the superheating chamber, and thus assures thorough and adequate preconditioning of the fuel under all conditionsY of operation.

I- have found the above feature to be of particular importance since When loperating the torch in inverted position, for example,- which is oftennecessary or desirable, fuel is forced into the superheating chamber in a liquid rather than a vaporized condition. And heretov fore, Where fuel Was being consumed at a high rate, such fuel was not adequately preconditioned and in many instances forced out the jet nozzle 20 while still in a liquid condition. Thorough and eicient combustion of the fuel was of course impossible under such conditions.

However, by the teachings of my present invention only a limited quantity of fuel may be Within the relatively minute passages of the superheating chamber at any instant, and such limited quantity of fuel is passed in intimate heat exchange relation to the burner nozzle 20 over a large area. So that even though fuel enters the superheating chamber in a liquid condition a thorough preconditioning is effected and combustion remains uniformly eicient.

My improved arrangement is advantageous not only from the standpoint of permitting uniform and eicient operation of the torch in any orientation, but further in that it permits a maximum heat output which is far in excess of that obtainable from prior torches of equivalent size. This may be explained by the fact that With prior torches attempts to consume fuel at excessive rates resulted in inecient combustion so that little or no increase in heat output Was alforded by increasing fuel consumption over a predetermined maximum amount, such maximum amount being substantially less than those contemplated in the operation of my torch.

Other advantages of my invention reside in improve- 6 ments'initorch construction', including, for example, `the construction Yof the topand 'side walls ofthetankf10'from va 'single body of aluminum whereby thetankuis of im proved strength and'appearanceand is characterized by improved and moreuniform Yheattransfer properties,tall of which is highly desirablefor tliepurposeintended:

Another important' advantage of my invention vresides in myimproved arrangementrfor constructing ern-elongate ed relatively restricted 4superheating chamber, :all parts of which are in intimate heat exchange relation with the burner nozzle 3.5 of the torch, which comprises providing a longitudinal bore in the top'wall of the'torch, immediately adjacent the nozzle 1S andinserting threaded concentrically disposed tubular and rod members 48v and 49 in the bore. This construction is highly compact as will be readily apparent, andlis in addition --easily carried out by production machining-processes, all of which'lends materially to the commercialappeal of the apparatus.

By mounting the burner nozzle 15 within the tubular nozzle holder 13, forming an integral partV of the-top rwall 11, lassure a maximum transfer of heat from the nozzle to the superheating chamber and to ythe body of fuel contained within the tank 10'. Anditwill'be understood thaty ambient conditions will-have-a minimum effect on the operation of the torch'by. virtue'of this construction. In addition, the vrateof transfer' of heat from the nozzle 15, and accordingly the equilibriumoperating. condition of. the torch may be'readily varied` by varying thesize and/ orv number of llands 16: onv they nozzle 15' whereby greater or less.` direct contact is aiforded' between the nozzle 15 and holder` 13;

It should be nnderstood,.however, that the embodiment ofimy invention hereindisclosed: and tspecically'described is intended to be representative only, andreferencesshould therefore' be `had.l to the appended claims in. determining the .true scope of the invention.v

I claim:

l. A blow torch comprisingaifuel'tank includingaiheat conducting wallhavin'g. an elongated cylindrical recess therein, a burnernozzle mounted on said tank iny close heatexehange relation-with said Wall, a' sleeve in said recess .coaxial'therevvitm spiralthreadmeans between the Walls of said recess and sleeve and forming a spirallfuel passage -o'f minute cross -sectiorralf area longitudinally thereof the inner end ofil which passage Vopens-"intol the innerA endl portion of saidvv recess, a rodi in said. sleeve closing the central portion thereof, 'spiral thread means between the insides of said sleeve and the exterior of said rod forming a spiral fuel passage of minute cross sectional area longitudinally of said rod and having the inner end opening into the inner end portion of said recess, the first mentioned thread means terminating short of the outer end of said sleeve and said sleeve having the outer end portion thereof in engagement with said recess Walls to close the outer end of the first mentioned fuel passage, said wall having a fuel passage connecting said tank with said recess and opening into said recess adjacent to one side of said portion of said sleeve and a fuel passage connecting said recess with said nozzle and opening into said recess adjacent to the other side of said portion of said sleeve, and a removable member for closing the outer end of said recess.

2. A blow torch comprising a fuel tank including a heat conducting wall having an elongated cylindrical recess therein, a burner nozzle mounted on said tank in close heat exchange relation with said wall, a sleeve in said recess coaxial therewith and having external spiral thread formations engaging the Walls of said recess and forming a spiral fuel passage of minute cross sectional area having the inner end thereof opening into the inner end portion of said recess, a rod in said sleeve closing the central portion thereof and having spiral threads engaging the inside of said sleeve and forming a spiral fuel passage of minute cross sectional area having the inner end thereof opening into the inner end portion of said tions` of said sleeve terminating short of said enlargedY outer end portion of said s1eeve,said wall having a fuel passage therein interconnectingsaid tank and said recess f and opening into said recess adjacent to one side of said shoulders and a fuel passage interconnecting said recessr and nozzle and opening into said recess adjacent to the opposite side of ,saidV shoulders, and a closure member removably'attached in the outer end of said recess,

3. A blow torch comprising a fuel tank including a heat conducting wall having an elongated cylindrical recess therein,` a burner nozzle mounted on said tank in close Yheat exchange relation with said wall, an externally threaded sleeve in said recess coaxial therewith and terminatingshort of the outer end thereof, the threads of said Sleeve engaging the walls of said recess and forming a spiral fuel passage of minute cross sectional area having the inner end thereof opening into the inner end portion of said recess, a rod in said sleeve closingthe central portion thereof and having spiral threads engaging the inside of said tubular member and forming a spiral fuel passage of minute cross sectional area having the inner end thereof opening into the inner end portion of said recess, said sleeve and recess having correspondingly enlarged outer end portions providing inwardly and outwardly facing shoulders respectively engaging one another to position said sleeve in said recess, said wall having a fuel passage therein interconnecting said tank and said recess and opening into said recess outwardly ofthe outer end of said sleeve and a fuel passage interconnecting said recess and nozzle and opening into said recessVV adjacent to the outer end Yofsaid threads on said sleeve and inwardly relative. to said enlarged portions of said sleeve and recess, and a closure member removably attached in the outer end of said recess.

4. Arself-generating blow torch comprising in combination'a hollow tank of highly heat conductive material for the direct reception of aV liquid volatile inflamv mable fuel, a burner ynozzle disposed Y longitudinally along one wall of said tank in intimate heat exchange contact therewithwhereby Vheat from said nozzle maybe Vconducted to the interior of said tank to volatilize fuel therein, said heat conductive tank including integral means along said one Wall thereof to receive said nozzle about itsV entire'periphery along a substantial portion* of its longitudinallextent, a fuel passageway communicating with the interior of said tank and leading `to said nozzle, said passageway Vincluding a highlynelongated restricted References Cited intherle of patent UNITED STATES PATENTS Re. 2,120 l Y Hayes Dec. 5, 1865 612,272 Pullen Oct.V 11, 1898 654,566 Gustafson Iulyr24, 1900 703,661 Y Lecomte July 1, 1902 872,500 Crane et al. Dec. 3, 1907 1,288,171 Pinal g 'Dec. 17, 1918 1,527,269 1 Peterson 1 .Felx 24, 1925 t l2,414,455 Dinklage Jan. 21, 1947 2,539,595 Schweitzer Jan. 30, 1951 Y Y 'FOREIGN 1 A TE1\ITSA Y p 47,709 switzerland May 18,1909. 27,859 Denmark f Iune11j`1921 t France Nov. 15,7195() Y tortuous chamber formed'in part by saidvheat conductive tank and dsposedin said one wall thereof closely adjacent said nozzle, and valve means in said passageway foi-conf` trolling the flow'of fuel to said nozzle.

5. A self-generating blow torch comprising in combination a hollow tankfor the direct reception of `liquid volatile iniiammable fuel, said tank having a wall ofA highly heat conductive material, a burner Vnozzle, disposed longitudinally along said wall in intimate heat exchange contact therewith whereby heat fromi'sadlnoz-V zle may be conducted to the interiorV of said tank to volatilize said fuel, apfuel passageway communicating with the interior of said tank andV leading vto said nozzle,

said passageway including a highly elongated restricted.

tortuous chamber positioned in intimate heatY exchange relation with said nozzle, and valve means inV said passageway for controlling the ow of fuel to said nozzle, said heat conductive wall having a portion of substantial thickness immediately adjacent'said nozzle and in intimate heat exchange relation therewith, said, chamber being contained wholly Within said thickened portion and comprising an elongated bore therein disposed generally parallel to said nozzle and means in said bore forming in cooperation with ythe walls thereof an elongated restricted spiral passage. 

